1. Field of the Invention
The present invention relates to a muffler hanger for suspending a muffler constituting the exhaust system of a vehicle in a vehicle body.
2. Description of the Related Art
From the past, muffler hangers have been known with which a muffler provided for the exhaust system of an automobile or the like is supported hung on the automobile underfloor or the like. As the muffler hanger, for example, as disclosed in U.S. Pat. No. 5,050,837, known is an item that is a rubber elastic body exhibiting an overall θ shape, and by both the upper and lower end parts being attached to each one of the vehicle body and the muffler, the muffler is elastically suspended on the vehicle body.
However, there were cases when there was a demand for hard spring characteristics in the vehicle front-back direction to align and hold the muffler in the front-back direction of the vehicle in relation to the vehicle body, and there was a demand for soft spring characteristics in the vehicle lateral direction and vertical direction to obtain a vibration isolation operation effect.
However, with the constitution noted in U.S. Pat. No. 5,050,837, not only in the vehicle vertical direction and lateral direction, but also in the front-back direction, the shear spring component becomes dominant with the spring characteristics, so it was difficult to set the spring to be hard in the front-back direction.
Also, with the muffler hanger of U.S. Pat. No. 5,050,837, while a displacement regulating means is provided for limiting the approaching displacement volume of the vehicle body and the muffler, a means for limiting the separation displacement volume of the vehicle body and the muffler is not provided, and there is the risk that if the vertical direction spring is set to be soft, the durability will be insufficient. Similarly, in the lateral direction of a vehicle for which the vertical direction spring is set to be soft as well, since the displacement regulating means is not provided, there are cases when sufficient durability in relation to large load input cannot be ensured.
In light of that, the muffler hanger of Japanese Unexamined Patent Publication No. JP-A-2010-242606 is constituted with a rubber elastic body that is attached to the muffler fixed to the inner surface of a tube-shaped metal fitting attached to the vehicle body, and by an attachment part to the muffler with the rubber elastic body abutting the inner surface of the metal fitting, the vertical direction and lateral direction displacement are regulated.
However, with the constitution of JP-A-2010-242606, since the spring characteristics in the front-back direction of the vehicle are mainly the shear spring component of the rubber elastic body, it is difficult to set the spring to be hard in the front-back direction, and it was difficult to effectively obtain the target spring characteristics.